Push button means

ABSTRACT

A construction is provided wherein a push-push button unit useful for operating electric switches as an example is provided. This push-push means has the property of being able to be ganged with similar push-push units to provide a multi-push button construction wherein each push button may be independently pushed to lock and again pushed to release, and in addition, is provided with a separate release button for unlocking all pushbuttons in the ganged construction which have previously been locked.

United States Patent [151 3,651,700 Bailey [45] Mar. 28, 1972 PUSH BUTTON MEANS Primary Examiner-Meyer Perlin [72] lnventor' James K Bailey Chicago Assistant Examiner -wesley S. Ratliff, Jr. 73] Assignee: Switchcraft, Inc., Chicago, ill. Attorney-Robert L. Kahn [22] Filed: June 22, 1970 App]. No.2 48,134

References Cited UNITED STATES PATENTS 6/1965 Cousins ..200/l53.9 1/1966 De Rougemont et a]. ..200/l53.9

[57] ABSTRACT A construction is provided wherein a push-push button unit useful for operating electric switches as an example is provided. This push-push means has the property of being able to be ganged with similar push-push units to provide a multi-push button construction wherein each push button may be independently pushed to-lock and again pushed to release, and in addition, is provided with a separate release button for unlocking all pushbuttons in the ganged construction which have previously been locked.

2 Claims, 13 Drawing Figures PATENTEmmzs 1912 SHEET 1 [IF 3 lnve'mor JAMES R BAILEY fi/ZTM I KM ATTY PATENTEUMAR28 I972 SHEET 2 [IF 3 PATENTEUMAR28 I972 SHEET 3 [IF 3 PUSH BUTTON MEANS This invention relates to a push button means and more particularly, to a push-push construction which may be used for operating electric switches or other devices.

A push-push device, such as an electric switch for example, has one or more push buttons (or push rod, actuator rod) which is normally biased to what may be designated as an OUT position, from which position a push will cause the mechanism to lock to an IN position. Release of the locked mechanism is possible by a push on the push button. The push button which is subject to a push-push action may be coupled in any suitable fashion to electric switch means, as an example, for changing the condition of such switch means depending upon whether the push button is OUT or IN. It is understood of course that instead of electric switch means, any suitable mechanical device may be controlled.

Push-push means have been well known and used for a long time. However, such push-push means have been subject to a functional drawback which has restricted the area of use of such means. Conventional push button means for operating switches or the like have come into wide use over the years. Such push button means have been susceptible to ganging so that pushing one button, for example, may release a previously operated button from a locked position to a normal position or not as desired, in which case a separate release button is so tied in with other push buttons as to release such other push buttons from a locked IN position. Consequently, conventional push button means (not having a push-push action) when ganged together are capable of some interlocking or common release action.

While push-push button means are old, the construction and operation of such means has up to now made it impossible to provide for release of any one or all locked push buttons apart from separately pushing each button independently of other buttons from a locked IN position to a released OUT position. For many applications of push button switches, it is desirable to have a row of push-push button or means so interlocked that an independent release button or means may function to release as many push-push buttons as desired from a locked to an unlocked position independently of the pushpush buttons.

A push-push construction embodying the present invention may be used independently of similar push-push button means and in addition, has the decided advantage of being susceptible to ganging with other similar push-push button structures for common release of such button.

An added advantage of the new structure is that any button which is locked to an IN position is definitely retained in such IN position, thus indicating from its position that the button as well as mechanism are both locked to any IN or LOCKED position.

The invention will now be described in connection with the drawings wherein:

FIG. 1 is a side elevation of a gang switch provided with individual push-push mechanisms embodying the present invention and with unlocking means independently of the new pushpush means.

FIG. 1A is a detail on line lA--1A of FIG. 1.

FIG. 2 is an exploded perspective view of a new push-push unit, showing the push button details.

FIG. 2A is a perspective view showing the reverse face of the floating pawl used in the unit, the obverse face of such pawl being shown in FIG. 2.

FIG. 3 is a sectional detail along line 33 of FIG. 4, this illustrating, in addition to the push-push construction, an exemplary construction for application of a push-push unit to an electric switch.

FIG. 4 is a side elevation showing the position of various parts of the push-push unit when the push button is in the normal OUT or UP position.

FIG. 5 is a view corresponding to FIG. 4 but showing the relative positions of parts when the push button has been moved DOWN or IN to the extreme temporary position in preparation for a partial return of the push button to a locked IN position.

FIG. 6 is a view corresponding to FIG. 5 showing the position of the various parts after the push button has been permitted to move to a locked IN position.

FIG. 7 is a view corresponding to FIG. 6 but showing the parts of a push-push unit when the push button has been pushed again toward its full down position after the locking position of FIG. 6 in preparation for the free upward travel of the push button to its normal OUT position shown in FIG. 4.

FIG. 8 is a plan view of the molded body for the push-push movement.

FIG. 9 is a side elevation of the body illustrated in FIG. 8.

FIGS. 10A and 10B are side and plan views of the floating pawl, the scales of FIGS. 8, 9, 10A and 10B being the same.

The push-push button construction includes a button body proper 10 molded of a suitable plastic. Push button 10 has free end portion 11 where a pushing force would be applied to force body 10 downwardly as seen, for example, in FIGS. 1 or 2. Push button body 10 is elongated, its length extending along a vertical line, as seen in FIGS. 1 or 2, and is supported for longitudinal travel within housing 14 preferably of metal. Housing 14 has sides 15 and 16 having a generally U shape. Housing 14 has front panel 18 and fingers 19 extending from sides 15 and 16. Fingers 19 serve to retain contact carrying insulating plate 21 which extends across housing sides 15 and 16.

Housing 14 has top edge 25 and bottom anchoring lug 26 extending away from front panel 18. Anchoring lug 26 has slot 27 and is adapted to accommodate fingers 28 and 29 of a frame plate 30. Fingers 28 and 29 are provided for one switch station upon frame plate 30, this plate being long enough to provide as many switch stations as desired. Retention of an operating unit in plate 30 at a desired station is obtained by twisting finger 28 upwardly from the plane of the drawing FIG. 1.

The detailed manner of supporting a push button operating unit (which can be the push-push unit to be described herein) and the frame construction is described in the copending application of Bailey and Lutzenberger, Ser. No. 761,174, filed Sept. 20, 1968, entitled Push Button Switch Means now U.S. Pat. No. 3,517,140 dated June 23, 1970. It is understood that the push-push means forming the subject matter of the present application may be mounted in any fashion and that such push-push means may be associated with any desired switch means or other means to be operated by a push button.

Referring to housing 14, front panel 18 has a generally reverse L shaped cutout 33 therethrough. The reverse L is slightly off center with respect to housing sides 14 and 15, so that straight vertical body portion 34a is a bit closer to side 16 of the housing. The extent and purpose of this offset will be explained later in connection with the operation of the mechanism. Vertical body portion 34a of the reverse L has top edge 34d canted at a small angle in the direction shown (away from L offset 35). Body portion 34a of the reverse L has its width generally constant from top edge 34d down for part of the length of body portion 34a and widens toward housing side 16 at portion 34b until the bottom edge of the cutout is reached.

Ofi'set 35 branches off to make a reverse L. Top edge 35a of offset 35 is canted as shown, in the same direction as edge 34d. The amount of cant is small, in the order of from about 2 to about 4 and the function of the cant will be explained later. It will be noted that the cutout body side is sloped away from offset 35 to provide room for a floating pawl (to be described) to work around the comer region where the offset branches off.

As illustrated here, reverse L offset 35 from the front of panel 18 extends to the left instead of conventional right. However, as will be readily understood after the entire construction has been described, the L structure may be reversed with respect to the direction of offset 35. In fact, as viewed from the rear of housing 14, L shaped cutout 33 will appear reversed and such reversal may be accomplished so that when viewed from the front of panel 18, the cutout will be as presently seen from the rear of panel 18.

Housing 14 is normally stationary and supports push button for longitudinal sliding motion. Push button 10 has its body recessed to provide guide and support areas within the recess. The recess in the side of push button 10 has side walls nearest free button end 11 shaped to provide a downwardly projecting V 40 whose bottom tip 41 is symmetrically disposed midway between side walls 42 and 43 of push button 10. V 40 has the upwardly sloping sides 40a and 40b thereof extending toward free end 11, the recess sides then extending laterally to provide bays 45 and 46. Bays 45 and 46 have the floors thereof level with recess floor 48. Recess shoulders 49 and 50, having generally triangular shape, rise from recess floor 48, these two shoulders having their free faces above recess floor 48 and somewhat below the level of the button face having the recess. Recess floor 48 extends away from the free end of push button 10 to reach step 52 having step top face 53. The level of step top face 53 and that of the free faces of shoulders 49 and 50 are the same. The recess and side walls in the side of push button 10 so far described are symmetrical with respect to a bisecting plane half way between sides 42 and 43 of the push button and parallel to such sides. The side walls of the recess extend generally perpendicular to recess floor 48.

Disposed within the recess in the side of push button 10 is floating pawl 56. This pawl has a generally flat shape with the reverse face provided with a generally T shaped relief portion 57 extending from body 58 of the pawl. T portion 57 has shoulder portions 57a and 5711 located on body 58 and the T additionally has pointed tip portion 60 extending beyond the edge of body 58. Body 58, on the obverse face as shown in FIG. 2 has shoulder portion 58a adjacent to tip 60, the shoulder extending away from tip portion 60 to provide shoulder sides 58b and 58c. Body 58 is substantially flat at the portion thereof defining shoulder 58a. However, shoulder sides 58b and 58c are perpendicular to the remainder of body 58, such remainder being flat.

The pawl dimensions and shape with respect to the dimensions and shape of the recess in the side of push button 10 are such that pawl 56 has limited movement on floor 48 within the recess in all directions in planes parallel to floor 48 of the recess.

The pawl is preferably of molded plastic tough enough to withstand wear. Extending laterally from the obverse face of pawl 56 and integral therewith is pin 65 having, as viewed from the end of the pin, flat 66 and generally rounded remaining body portion. Flat 66 is oriented on that side of pin 65 which is nearest tip 60 of the pawl. Flat 66 extends straight along the pin length but is canted, as seen in FIGS. 2, 4 to 7 inclusive, clockwise. The amount of cant offlat 66 is of the same order as that of L edges 34d and 35a. The amount of cant in all instances may vary, depending upon such factors as dimensions of the various parts, nature of materials involved, etc., and desired operating characteristics.

The transverse dimensions of pin 65 and the length of the pin are such that, when the pawl is disposed within the push button recess and when the push button has housing 14 covering such recess, pin 65 will extend through a part of the L in the housing and be able to travel along the L cutout. The function of the pawl and recess shapes is to provide cooperative cam and follower action when movement of push button 10 forces pin 65 to travel along the L. The relative surfaces of the recess and floating pawl cooperate to permit movement and rocking of the pawl to various positions determined by the relative location of pin 65 in the L of housing 14.

In general, the reverse face of pawl 56 has pawl part 57 resting upon the floor of recess 48 while the inwardly offset portion of pawl body 58 (as viewed from the reverse face) will rest upon step face 53. Step 52 acts as a stop for shoulders 57a and 57b. Tip 60 will play within bays 45 and 46 while shoulders 49 and 50 limit rocking of the pawl.

The cooperation between pawl and recess is accomplished not only by the guiding action between pin 65 and the sides or edge of the housing along the L cutout, but additionally by light V spring 70 having anchor portion 71 normally lying in bed slot 72 at one side of push button 10, such slot being in the same face of the push button as the recess previously described. V spring 70 is for the purpose of biasing pawl 56 and to this end has portions 71a and 71b shaped to form a V and so disposed as to extend across the obverse face of pawl body 58 below pin 65 as seen in FIG. 2, with spring portion 71b extending upwardly to engage the bottom rounded portion of pin 65. As previously pointed out, pawl 56 has sufficient room within the recess to permit play in such recess. Spring 70 will normally urge pawl 56 upwardly as seen in FIG. 2 toward V portion 40 of the push button.

Push button 10 is normally biased to its UP position, as shown in FIG. 4, for example, by compression spring 75 disposed in bias spring bed 76 provided in the bottom portion of push button 10. Push button 10 has stop 77 projecting laterally from the recessed face of the push button to function as a stop for one end of coil spring 75. The other end of this coil spring rests against the lower spring stop 78 forming part of housing 14.

Housing 14 has window 79 for accommodating the outwardly bulging portion of coil spring 75. Coil spring 75 is considerably stronger than pawl bias spring 70 and will normally oppose the action of spring 70 at certain cycles of operation.

The push-push movement is conveniently associated with electric switching means, an example of which is illustrated in FIG. 3. Thus insulating board 21 carrying fixed contacts is secured in place against a side face of push button 10 and is maintained in fixed position to housing 14 by fingers 19 extending over notches in board 21. The push button surface opposite contact board 21 is suitably shaped to accommodate some movable contacts. This general switch construction is more fully described in the copending application previously referred to.

FIGS. 8, 9, 10A and 108 show to the same scale floating pawl 56 and the recess in push button 10 within which the pawl operates. T shaped relief portion 57 is flat and normally rests upon floor 48 of the recess. Shoulder portion 570 can rest against step 52 when the pawl is forced against the same. In such a position, tip portion will normally be short of edge 41 of V 40 with the pawl axis laterally offset to the right of the pawl center line so that tip 60 is short of V edge 41 and slightly to the right as seen in FIGS. 2 and 4. There is enough clearance in recess 48 so that shoulder portion 57c need not necessarily be always in contact with step 52 and permits some rocking at appropriate times of pawl 56 to direct tip 60 of the pawl either to one side or the other side of V 40. Once pawl 56 has been rocked so that tip 60 is either to one side of V tip 40 or the other, bays 45 and 46 permit pawl 56 to move upwardly with reference to recess 48 (as seen in FIGS. 4 to 9 inclusive) and at the same time tends to cause the pawl to rock further. The upward travel in recess 48 of floating pawl 56 will move shoulder 570 clear of step 52 to permit rocking of the pawl. Body portion 58, particularly, that part extending below the bottom of pin 65, as seen in FIG. 10A, functions principally as a stabilizing surface resting upon shelf 53 of the recess and its presence is desirable due to the small dimensions and extent of the various cooperating guiding surfaces on the floating pawl as well as in the recess of push button 10.

Normally, as illustrated in FIG. 4, compression spring 75 urges push button 10 to its UP position wherein pin is at the top of the L body 33. Flat 66 engages top edge 34d and causes floating pawl 56 to be in the position shown in FIG. 4 where pointed tip 60 is somewhat to the right of V tip 41. Due to the fact that spring 75 is quite powerful, compared to V spring 70, the normal position of the mechanism illustrated in FIG. 4 results in portion 71b of V spring being urged downwardly somewhat.

The limit of upward travel of button 10 within housing 14 is determined by pin 65 reaching top edge 34d of the body of reverse L cutout 33. This causes pawl 56 to move so that pawl shoulder 57c bears against step 52 in recess 58. However to protect pin 65 against being sheared when spring is suddenly released and snaps button 10 upwardly, it is preferred to have stop 77 at the lower part of button 10 first engage the top edge of window 79 of housing 14, this to occur before pin 65 is completely stopped by top edge 34d of the reverse L cutout. This stopping action occurs before tip 60 reaches V edge 41. V spring 70 permits some lost motion of the pawl and pin when pin 65 initially engages top L edge 34d. In the position illustrated in FIG. 4 of the drawing, the floating pawl has shoulder 57c resting upon step 52 with longitudinal pawl axis 600 laterally offset a bit to the right of the button center line as illustrated in FIG. 4. Thus in the normal OUT position of button 10, the floating pawl will have its axis as described with tip 60 offset and below V edge 41.

The engagement of canted flat 66 of pin 65 against canted edge 34d'in the reverse L cutout serves to stabilize the position of the floating pawl. The cant of edge 34d may be omitted if desired although it is preferred to retain the same. The top portion of the body of the reverse L is just wide enough so that pin 65 is maintained in the position illustrated in FIG. 4.

When push button is moved from full OUT position illustrated in FIG. 4 toward the down position illustrated in FIG. 5, the first part of the button downward travel permits lost motion of V spring 70 and results in pin 65 remaining at the top edge of 34d of the reverse L with tip 60 of the pawl engaging side 40b of the V and being rocked into bay 46 past V tip 41. This causes the pawl to be rocked, shoulder 57c leaving part or all of step 52 and rocking the entire pawl generally clockwise to the position shown in FIG. 5. During this rocking of the pawl, pin 65 has traveled downwardly into the cutout wider portion 34b to permit pawl rocking to occur. As push button 10 approaches the bottom of the reverse L, the rocking of the floating pawl causes pin 65 to turn the reverse L comer and enter offset 35. When the push button is released from its extreme down position, illustrated in FIG. 5, strong spring 75 will urge push button 10 upwardly and the adjacent comer part of pin 65 will catch against top edge 35a and lock button I0 against further upward travel, the various parts occupying the position shown in FIG. 6. The cant for edge 35a cooperates with the cant of flat 66 of the pin to maintain the various parts in an IN position. The amount of cant to offset edge 35a and edge 34d may vary and the cants may be omitted.

In the position of the mechanism illustrated in FIG. 6, Iongitudinal axis 60a of the floating pawl is parallel to the longitudinal axis of button 10, as in FIG. 4, with the difference however that the floating pawl has now been laterally shifted so that pawl tip 60 is to the left of V edge 41 and can be in a position to enter bay 45. In this position in FIG. 6, the floating pawl has its T shoulder 57c squared against step 52. In order to unlock the mechanism from the position illustrated in FIG. 6, downward pressure of button 10 will cause rounded tip 60 of the pawl to operate in bay 45 and cause the pawl to be rocked in a counterclockwise direction. In such a condition, the pawl turns the corner from offset 35 and when button 10 is released, the floating pawl moves down with respect to the recess in button 10 to cause pointed tip 60 to drop below V edge 41 and when pin 65 reaches the upper portion of the body of the reverse L cutout, the floating pawl has been rocked and moved to the position generally illustrated in FIG. 4.

A push-push mechanism as disclosed herein with floating pawl pin 65 movable over a definite horizontal range is ganged with similar push-push movements in laterally offset relation, as seen in FIG. I for example. Each such push-push unit has its individual push button 10 with its own push-push movement complete. Each push-push unit is secured to frame plate as hereinbefore described. Frame plate 30 has large window 30A for each switch unit station. Insofar as a push-push unit is concerned, each one is independent of other units. For releasing push-push units from locked IN positions, a special release station is provided. Such special release station may be located anywhere along a ganged switch array (as at one end, for example) and has a special release push button 86. Release button 86 may be any conventional push button, working with or without electric switches and normally biased to an UP position. Release button 86 is normally movable against its bias to a down position and when free will return to its UP position.

The release arrangement provides for longitudinal travel of release plate in a direction normal to that of travel of release button 86 when the same is forced downwardly as seen in FIG. 1. Release plate 85 is hung on frame plate 30,-is normally biased to the left (FIGS. 1 and 1A) and is moved to the right when release button 86 is forced down. Push button 86 carries cam block 87 which extends laterally from button 86 through large window 30A of frame plate 30 and through window 88 of release plate 85. Window 88 of plate 85 has cam edge 89 which causes release plate 85 to move to the right a limited distance when button 86 is forced down. This construction and action is fully disclosed in the copending application previously identified.

Release plate 85 carries unlocking finger 91 for each floating pawl pin 65 of a push-push unit. Each finger 91 is positioned so that movement of plate 85 to the right, as seen in FIGS. 1 and 1A, will cause each finger 91 to engage the corresponding floating pawl pin 65 only when pin 65 is in looking position (see FIG. 6) and forces such pin to move to the right sufficiently so that each pawl pin 65 can bemoved from an L offset 35 into the vertical portion of the body of the L. When a floating pawl pin is forced into that position, clear of L offset 35, compression spring 75 of each push-push unit will function to return every push button 10 to a normal UP position. Fingers 91 should be narrow enough so that any pawl pin 65 will be cleared when not in a locking position.

For convenience, as shown in FIG. 1A, a pair of fingers 91 are illustrated as being riveted at 93 to release plate 85. However, any other arrangement providing for fingers 91 carried by plate 85 adapted to be moved into engagement with floating pawl pins 65 of push button units when such push button units are in locked position may be used. The arrangement is convenient in that release plate 85 and frame 30 permits the use of generally similar parts as illustrated in the construction disclosed in the previously identified application.

As many push-push units as desired may be ganged to form a multistation combination. It is not necessary that every pushpush unit in an array be provided with an unlocking finger 91. One unlocking button, such as 86, may be provided for pushpush units in one general switch array and a separate unlocking button may be provided for additional push-push units.

For convenience, OUT or UP and IN or DOWN are used, interchangeably. The same is true of push button of push-rod.

Variations in the dimensions of the reverse L cutout, the dimensions of portions of the recess in push button 10 and floating pawl dimensions and shape may be made for determining the length of push button stroke, the amount of return travel of a push button to reach a stable IN position or the amount of floating pawl travel and rocking. Insofar as the release button is concerned, it may or may not have switch means associated with it. Other means than a push button may be utilized for actuation of release plate 85 or any finger 91.

What is claimed is:

l. A structure for push-push operation of electric switches or the like, said structure having a push-rod having a free end for pushing the rod longitudinally and having a rod side recessed, stationary housing means for supporting said rod for longitudinal travel over a limited range from a normal OUT position to a full but temporary IN position, said housing including a cover portion lying over the recess and having an L shaped opening therethrough, the body of the L extending in the direction of rod travel with the L ofiset bottom furthest from the rod free end, spring means biasing said push-rod to said OUT position in said housing, a generally flat floating pawl in said recess having one face immediately adjacent the inner face of the housing cover portion and carrying a pin extending laterally from said one pawl face through the L shaped opening in said cover portion, said pin having a flat and being small enough to ride along the L during rod movement in said housing, said pawl normally having clearance in the recess to move in all directions in a plane normal to the pin length, said recess having the end portion nearest the free rod end shaped to provide a V whose tip points away from the free rod end, said pawl having a pointed tip nonnally extending toward the general direction of the V portion of the recess, spring means acting between the rod and pawl tending to bias the pawl in said recess toward the V, said last named spring means providing a bias which is substantially weaker than the first named spring bias of the rod in its housing, said push-rod when approaching its normal OUT position pressing the pawl against the recess end furthest from the V to square the pawl toward one V side before the pawl tip reaches the V tip, said push rod when being pushed from its normal OUT position toward the extreme IN position acting on the pawl tip to push said tip deep along the V one side to further rock the pawl as the pin travels along the body of the L toward the offset so that when the rod reaches its temporary extreme IN position, one V side rocks the pawl to direct the pin into the L offset, the end of pushing pressure upon the rod end permitting the rod to respond to its bias and move outwardly a short distance at which the pawl tip is clear of the V and the pin flat catches against the offset edge of the L opening, to rock the pawl to point the pawl tip toward the other V side, the pin still being in the L ofiset to hold the rod in a stable intermediate position, when pushing said rod from the stable intermediate position toward the full IN position, causing the rod V in the recess to be engaged by the pointed pawl tip at the other V side and rock the pawl so that the pin is moved out of the L offset to the adjacent end of the L body, after which release of the rod permits the rod bias to return the rod to its normal OUT position with the aforementioned rocking action of the pawl points the pawl to cooperate with the one V side, the width of the L opening and length of the L offset being sufficient to cooperate with the pin so that said pin can easily travel in the L path.

2. The construction according to claim 1 wherein an array of individual push-push structures are mounted in laterally offset parallel ganged relation so that the free ends of the push rods, when all such push rods are in a normal OUT position, extend along a straight line, the individual structures being arranged so that the corresponding cover portions for the housings face in the same direction, the L offsets of the individual structures being aligned, a release bar extending adjacent the ganged structures close to the cover portion in a direction parallel to the aligned L offsets, the release bar being movable longitudinally and long enough to extend along the array of the push-push structures, the range of travel of such release bar being generally equal to the distance between adjacent L offsets, said release bar carrying a finger corresponding to each individual push-push structure and extending laterally from said release bar toward the cover plate of a push-push structure, the dimensions of said finger and the location with respect to the L offset being such that the finger can engage a pin of a push-push structure when said pin has its fiat catching against the edge of the L opening, the normal position of said release bar having each finger clear of the pin of its corresponding push-push unit even when said pin is resting against the offset edge of the L opening, each finger being movable with said release bar for release purposes to push its cooperating pin for release purposes, the fingers on said release bar being operative to release all locked push-push structures to permit all the push rods to return to normal OUT position from a previously locked down position, means for moving said release bar from one position where the individual fingers always clear the pin ends to a release position where all fingers can engage every pin which is in the Locked In position, each push-push structure being mechanically and functionally independent of all remaining push-push structures but being susceptible to a common release action. 

1. A structure for push-push operation of electric switches or the like, said structure having a push-rod having a free end for pushing the rod longitudinally and having a rod side recessed, stationary housing means for supporting said rod for longitudinal travel over a limited range from a normal OUT position to a full but temporary IN position, said housing including a cover portion lying over the recess and having an L shaped opening therethrough, the body of the L extending in the direction of rod travel with the L offset bottom furthest from the rod free end, spring means biasing said push-rod to said OUT position in said housing, a generally flat floating pawl in said recess having one face immediately adjacent the inner face of the housing cover portion and carrying a pin extending laterally from said one pawl face through the L shaped opening in said cover portion, said pin having a flat and being small enough to ride along the L during rod movement in said housing, said pawl normally having clearance in the recess to move in all directions in a plane normal to the pin length, said recess having the end portion nearest the free rod end shaped to provide a V whose tip points away from the free rod end, said pawl having a pointed tip normally extending toward the general direction of the V portion of the recess, spring means acting between the rod and pawl tending to bias the pawl in said recess toward the V, said last named spring means providing a bias which is substantially weaker than the first named spring bias of the rod in its housing, said push-rod when approaching its normal OUT position pressing the pawl against the recess end furthest from the V to square the pawl toward one V side before the pawl tip reaches the V tip, said push rod when being pushed from its normal OUT position toward the extreme IN position acting on the pawl tip to push said tip deep along the V one side to further rock the pawl as the pin travels along the bodY of the L toward the offset so that when the rod reaches its temporary extreme IN position, one V side rocks the pawl to direct the pin into the L offset, the end of pushing pressure upon the rod end permitting the rod to respond to its bias and move outwardly a short distance at which the pawl tip is clear of the V and the pin flat catches against the offset edge of the L opening, to rock the pawl to point the pawl tip toward the other V side, the pin still being in the L offset to hold the rod in a stable intermediate position, when pushing said rod from the stable intermediate position toward the full IN position, causing the rod V in the recess to be engaged by the pointed pawl tip at the other V side and rock the pawl so that the pin is moved out of the L offset to the adjacent end of the L body, after which release of the rod permits the rod bias to return the rod to its normal OUT position with the aforementioned rocking action of the pawl points the pawl to cooperate with the one V side, the width of the L opening and length of the L offset being sufficient to cooperate with the pin so that said pin can easily travel in the L path.
 2. The construction according to claim 1 wherein an array of individual push-push structures are mounted in laterally offset parallel ganged relation so that the free ends of the push rods, when all such push rods are in a normal OUT position, extend along a straight line, the individual structures being arranged so that the corresponding cover portions for the housings face in the same direction, the L offsets of the individual structures being aligned, a release bar extending adjacent the ganged structures close to the cover portion in a direction parallel to the aligned L offsets, the release bar being movable longitudinally and long enough to extend along the array of the push-push structures, the range of travel of such release bar being generally equal to the distance between adjacent L offsets, said release bar carrying a finger corresponding to each individual push-push structure and extending laterally from said release bar toward the cover plate of a push-push structure, the dimensions of said finger and the location with respect to the L offset being such that the finger can engage a pin of a push-push structure when said pin has its flat catching against the edge of the L opening, the normal position of said release bar having each finger clear of the pin of its corresponding push-push unit even when said pin is resting against the offset edge of the L opening, each finger being movable with said release bar for release purposes to push its cooperating pin for release purposes, the fingers on said release bar being operative to release all locked push-push structures to permit all the push rods to return to normal OUT position from a previously locked down position, means for moving said release bar from one position where the individual fingers always clear the pin ends to a release position where all fingers can engage every pin which is in the Locked In position, each push-push structure being mechanically and functionally independent of all remaining push-push structures but being susceptible to a common release action. 